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(11) | EP 0 671 691 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Storage controller and bus control method for use therewith |
(57) A storage controller (2; 2a) comprising a storage device adapter (22; 522), a channel
adapter (21a, 21b; 521a, 521b), a cache memory (24), a control memory (23), and a
plurality of buses (26, 27; 56-58) connecting therebetween. The channel adapter communicates
with a processor (1) and processes input/output requests issued by the processor.
The storage device adapter controls a storage device (3) and data transfer between
the storage device and the cache memory. The channel adapter and the storage device
adapter exchanges control information via the control memory. The buses are used to
transfer the data and the control information between the cache memory and the control
memory, and the channel adapter and the storage device adapter. The controller also
comprises bus load estimating means and bus mode selecting means. The bus load estimating
means (201, 202) estimates bus load characteristics as an index based on the amount
of data transfer during sequential access to the storage device. The bus mode selecting
means (203) determines a bus mode of bus utilization based on the index. Each of the
channel adapter and the storage device adapter has bus access means for accessing
the buses in accordance with the bus mode selected by the bus mode selecting means. |